Optimize broiler growth and welfare with correct ventilation systems

Broiler production systems that are used all over the world create a need for flexible and reliable ventilation solutions. When mentioning flexibility, the one thing that should not be flexible or random is the cost of running that same ventilation system. Farmers and growers want to know that their ventilation system performs well, but also what the operational costs are and what they will be.

Most broilers today are floor-raised on litter in large structures, which are climate controlled. If there is a sudden cold spell, the system needs to be prepared for adding the right amount of heating power and a system for emergency opening when there is a power loss. Other requirements on the ventilation system are that it should be able to accommodate a day old chick weighing around 40-45 grams to a fully grown bird of 2,500 grams or more. Suitable temperature and humidity levels in the house vary with the bird’s growing cycle and ambient conditions from the climate zone where the house is built.

All of the above coupled with sufficient feed and water access make the broilers comfortable and healthy, suitable to become food for humans. A healthy, closed indoor environment often means that the grower needs to spend less money on medicine for the birds, a cost saving that Munters have seen decreased with as much as 40%.

Having stated the above, it is very important to choose an energy efficient and well performing climate control system that fits the production system, and also with the objective for the farmer/ grower to have as low Total Cost of Ownership (TOC) as possible, to increase farm profit.

Let us look at which parameters should be focused on when meeting a farmer. In most cases the building structure and size has been chosen by the farmer already, which more or less decides the layout and design of the ventilation system. The next thing to take into consideration is the ambient climate condition of the specific location. Average winter & summer temperatures, humidity levels and other specific weather types that the climate control system needs to be ready for, are carefully collected and investigated. The control at the heart of the system will be configured so that it responds to changes in temperature, humidity and e.g. strong winds. It should also have preset temperature curves adapted to the growing cycle of day old chick until the bird is ready for processing plant.

In a large broiler house there are some design challenges and they are all more or less unique to every house one comes across, but it is possible to outline some general challenges. One important challenge is to create uniformity. With the birds being free to move around the broiler house, this is an essential challenge. Uniformity means there can be no cold or warm spots in the house. If that occurs during cold periods, the broilers will be clustered around warmer spots and there is a risk of disturbances, such as fighting in the flock. The same scenario of clustering will occur during warm periods if there are cooler spots, likewise creating an imbalance in the house.

Uniformity always starts with placement of the climate equipment for an even distribution of fresh incoming air and taking stale air out of the house. The type of inlet chosen depends on the climate conditions where the house is located. If the incoming air is cold for a period of the year, one generally wants to avoid that cold air drops down directly towards the birds, something which will inevitably disturb them and cause a non-uniform climate. For these cases, a horizontal and radial spread of air is desired which will mix it with warmer air next to the attic or ceiling before it drops down on the flock.

In the design phase, attention should also be paid to the distance between the ceiling/attic air inlets so that the optimum air flow inside the building can be reached.

How do we know that we got it right? Well, there is no second chance; we have to design it correctly from the start. We get a receipt that it is working when you see that the birds are uniformly spread in the house.

When you visit a broiler house you will most probably find it a dusty and greasy environment with feathers all over. These kinds of deposits are normally occurring at any farm, especially towards the end of a flock. It is not possible to go and clean the ventilation equipment during a cycle without considerably disturbing the animals and causing wet litter etc. Before the flock is replaced, the entire house including equipment can be hosed down with high-pressure cleaners and disinfectants. Ventilation equipment should be adapted to these environments, being both dirty and containing high acidity levels.

The second challenge for a climate control system is bedding quality at least for floor production systems where birds move around on the floor. This typically consists of straw, wood shavings or sand.

The broiler farmer wants the bedding material to remain dry so that it does not stick to the birds’ feet thereby causing lesions. Wet bedding material mixed with manure will increase the ammonia levels inside the house, affecting both animals and people negatively. A well ventilated building with sufficient air flow and heating on a need basis will ensure that the bedding material is kept dry. So there are lots to win for the grower when it comes to keeping the bedding material dry; and it all spells better farm economy and better animal welfare.

In some parts of the world, ammoniaemissions are restricted by law especially in areas that are densely populated. In these areas the grower stands at risk of not being able to expand their production because of the concentration of ammonia emission from the site. This can however be solved in different ways. The most common one being a scrubber solution, which literally washes the ammonia out of the stable air before it is let out into the atmosphere. One major challenge in this respect has been filters that clog up and need to be replaced at a regular pace, often at high cost. Since a couple of years back, Munters realized that we could use another of the company’s core technologies, mist elimination, to come around this problem. Today the ammonia emissions are reduced by up to as much as 89% on average, and with maintenance limited to high pressure cleaning of the mist eliminators every now and then.

The third challenge revolves around heat waves and periods of hot weather that appear both unexpectedly and temporarily. The consequences are however disastrous to the grower, resulting in lower production and increased mortality in the flock. A temperature range specific to the age of bird, starting from34 °C and ending at 18 °C depending on breed and other local variables – without humidity extremes – these are the climate conditions that have been generally found to be optimal, for growth performance as well as for animal welfare.

Light control plays an important role in modern poultry farming and here it represents the fourth climate challenge. Having adequate light control enables a grower to reap benefits by achieving excellent production results since the broilers need a few hours of sleep (as recommended by breed suppliers) in order to grow properly. The house does not need to be absolutely pitch-dark, but it is necessary to create a brown out effect in the house and to avoid light spots. A practical problem here is the necessity for ventilation openings in the structure. These allow for fresh air to enter as well as for the extraction of stale air. Unfortunately, daylight penetrates the structure through both the air inlets and exhaust openings. Light filters are used to solve this problem, allowing air movement through, but absorbing the light. Other ways to avoid light spots would be to use drip pans underneath chimney fans and deflector disks of ceiling inlets reflecting the light from outside back up towards the ceiling or walls. The reflected light does not prevent the birds from getting their rest. By properly configuring the climate system and equipping each project with the products and accessories suitable for that specific location, we can make sure that the farmer doesn’t end up with exhausted animals that don’t thrive or perform well.

An unstable energy supply is the fifth challenge in intensive broiler farming. Inlets and extraction openings are handled by actuators regulated by a controller. If a power failure occurs, there must be a backup system connected to the controller, which makes sure that the birds are not suffocating. The inlets and fan dampers will automatically be set wide open, ensuring sufficient natural ventilation airflow in case of an emergency such as power loss.

Set at the heart of each climate control system, you will find a number of controllers which orchestrate the equipment. The silo controller, which controls the chicken feed, the general temperature controller with extra sensors that monitor CO2levels and lets the farmer set temperature curves for the building(s), control the minimum ventilation and tracking historical data from the house.

Intensive poultry farming of today deals with a highly competitive landscape, with limited financial margins. Therefor it is of outmost importance to safeguard the investment made and to let it materialize in a stable and even production at all times.